You can get screws that have a drill point built right into the screw, they work great for thin metal even up to 3/16" or more. You can also get self tapping screws that will cut their own threads but require a hole to be drilled first. For these use a twist drill bit of the appropriate size to create the pilot hole.

For driving either type of screw a cordless drill or cordless impact driver works best. You need slower speeds and higher torque. You must be careful as the screws get tight, as the screw head bottoms out or the screw will often snap off if the screw is over tightened. A cordless drill with a clutch is a good option.

If they are sheet metal screws, I just punch a hole with an awl. Be careful not to punch the hole too big. If they are self drilling, run them with a battery drill. They'll make their own hole and start threading. Some self threading screws need a pilot hole. In that case, drill the absolute smallest hole that the tip will start into.

If they are sheet metal screws, I just punch a hole with an awl. Be careful not to punch the hole too big. If they are self drilling, run them with a battery drill. They'll make their own hole and start threading. Some self threading screws need a pilot hole. In that case, drill the absolute smallest hole that the tip will start into.

I use an awl as well, and it makes the installation much, much easier. For corrugated steel roof/ceiling/siding, I wouldn't think of any better way that creating a pattern sheet, and using an awl to pre-punch all the holes before installing. A few minutes on the front-end will save you hours and lot's of frustration on the back-end..............

I was off topic because my example is for tapping for regular threaded screws not self tapping screws.
I always thought of self tapping screws as NOT requiring a pilot hole but now I see that sometimes sheet metal screws are being referred to as self tapping screws.

The O.P. did not clarify which type but now I think he is referring to regular sheet metal screws which do require a pilot hole.

The Self-Tapping screws pictured do NOT need a pilot hole.
My use of the Drill & Tap tool has been for adding Green Ground Screws in old style Electrical boxes that did not have a ground screw. That style Drill & Tap would not work for thin sheet metal.

Answer

Using an impact on self tapping screws is usually difficult. An impact is easier on thick metal but still difficult, but if you are trying to go through thick steel (1/8" -1/4") you need to not only use a regular high speed drill but you will also need to buy what I have always called badass screws (doubt that's the manf name). They are similar to the self tapping screws pictured in the above post but the drill/tap flights are about 1/2" long vs 1/8. AMAZING SCREWS. Expensive, but amazing.

They also have self tapping screws that cut their own threads but require a pilot hole. Much cheaper but again they require a pilot hole.